EGR system in a turbocharged and intercooled HD diesel engine - expansion of EGR area with Venturi EGR system

摘要

In a turbocharged and intercooled HD diesel engine, it is difficult for conventional EGR system to get high EGR rate at high load. To solve the problem, Venturi EGR system were experimentally evaluated, and was optimized for 12L HD diesel engine. As a result, venturi system could make EGR over the all engine operating area, while conventional EGR system could not obtain any EGR rate over 50% engine load. For example, prototype venturi EGR system could obtain about 6% ECIR rate up to full load with lower pumping-loss than use of exhaust choke valve which was confirmed by measuring cylinder pressure diagram. It is concluded that venturi EGR system is, therefore, one of the most useful method to realize high EGR rate at high engine load without fuel consumption penalty.